Preparation and ablation behavior of a ZrB2-SiC coating-matrix integrated C/C composite

Abstract

The preparation of a ZrB2-SiC coating-matrix integrated C/C composite was achieved by a slurry method and precursor infiltration and pyrolysis. The obtained composites consisted of a SiC outer layer, a ZrB2-SiC inner layer and a C/C-ZrB2-SiC substrate. Compared with a composite without the ZrB2-SiC layer, the mass ablation rates of the composite were reduced by 14.8 %, 12.0 %, and 19.4 %, and the linear ablation rates were reduced by 41.3 %, 28.2 %, and 14 %, respectively, after ablation under an oxyacetylene flame with a heat flux of 4.18 MW/m2 for 60 s, 120 s, and 300 s. During the ablation process, the SiC outer layer played a role in reducing the heating rate and surface temperature and promoting the sintering of ZrO2 so that the oxide layer avoided peeling off under large thermal stress. The ZrB2-SiC inner layer acted as an oxygen, heat and flow barrier, reducing the oxidation rate of the substrate.